Police arrest Karen Read for the murder of her Boston cop boyfriend.

As the trial begins, witnesses claim they heard Karen say, “I hit him.”

As the trial continues, more details emerge about allegedly sloppy evidence collection, conflicting testimonies, manipulated video footage, and baffling DNA results. Karen’s team suggests a conspiracy and cover-up are at play.

The jury hears shocking testimony about Karen's alleged affair, scandalous texts, mysterious butt dials and conflicting Google search timestamps. Some dub Karen "America's Happiest Murder Defendant," and the conflict in Canton grows.

As the trial winds down, experts attempt to recreate John’s death, the defense brings in one final witness and closing arguments grip the nation. Karen, emotional after a long haul, anxiously awaits her fate. The jury returns with an unexpected note.